Field of the Invention
The disclosed technology relates to the field of bio-medical applications, and more particularly, to the present invention relates to packaging methods for components, such as chips, for bio-medical in vivo applications and packaged devices thus obtained.
Description of the Related Technology
Implantable chips are used in bio-medical in vivo applications e.g. for performing controlling or monitoring functions. Such implantable chips should be packaged to protect the body from leakage of harmful products from the chip towards the body, or from other harmful influences such as mechanical friction of the implanted chip in the body. Furthermore, the chip should be protected from influences from the body, such as diffusion from bio-products from the body into the chip, resulting in damaging or improper functioning of the chip.
A known way of packaging chips for medical applications takes care of the required bi-directional protection, by placing the chip in a ‘big box’, often a Titanium housing surrounding a chip mounted on a printed circuit board PCB. In this known way of packaging, the package is large in comparison with the size of the original chip, requiring larger incisions during implantation, thus resulting in a more extensive wound healing and inflammation process. Furthermore, the larger the implant, the larger the fibrous encapsulation may be resulting in a higher risk on local tissue irritation for the patient during the lifetime of the implant. When applying the ‘big box’ packaging technique, the chip itself often also is packaged with an individual standard package, before it is mounted on the PCB.
By way of illustration, cross sectional views of two types of conventional chip packages are shown. In a first example in FIG. 1a, a chip 100 having an individual package 110 is shown whereby metal wires 120 are provided for connecting the individually packaged chip to the PCB 130. The device is furthermore packed completely in a device housing 140. As the standard individual chip packaging is not bio-compatible, the second packaging, referred to as the device housing 140 here definitely is required resulting in a much higher total packaging cost. In FIG. 1b, packaging of a chip 100 that is mounted directly on the PCB whereby only a single packaging is present, being the device housing 140. In this case the chip is not packaged individually and there is a risk of chip contamination or damage, resulting in device malfunctioning. The individual packaging of chips as illustrated by FIG. 1a, has the disadvantage of being a time consuming and expensive process, as all chips conventionally are packaged individually.
U.S. Pat. No. 7,371,693 B2 describes a glass-based device wherein chip sized packaging is performed by separation of individual dies using wet etching of a groove between dies. The wet etching furthermore has a rounding effect for the sharp edges of the dies. The document furthermore describes the provision of a protection film. The protection film is not provided to hermetically encapsulate the device